1. Field of the Invention
The preferred embodiments of the present invention are directed to batteries. More particularly, the preferred embodiments of the present invention are directed to consecutively wound or stacked battery cells and battery systems.
2. Description of the Related Art
It is common in the battery industry to build battery cells by winding long sheets of anode material and cathode material, separated by a porous layer, around a mandrel to form a generally circular single cell battery. After the winding process completes, some form of liquid or viscous electrolyte is inserted, usually into a hole at the center of the circular winding, and the electrolyte is allowed to fill the porous layer between the anode and the cathode sheets. U.S. Pat. No. 4,975,095 to Strickland et al. exemplifies a method and related system for performing the related art winding of a cell, with the central opening 72 of the winding (see FIG. 6) being the location where liquid electrolyte is forced into the winding. Windings for battery cells need not be circular however. U.S. Pat. No. 6,190,794 to Wyser is exemplary of a system where the winding is non-circular, in this case elliptical, as is the disclosure of U.S. Pat. No. 5,746,780 to Narukawa, et al.
Whether circular or elliptical, related art battery windings are only a single cell, and therefore only operate at a single voltage; however, many modem electronic devices need multiple voltages to operate correctly. U.S. Pat. No. 6,038,473 (hereinafter the '473 patent) to Olson et al. describes a defibrillator battery pack in which one set of individual battery cells is used to charge the defibrillator, and a second set of individual battery cells is used to produce an operating voltage for control electronics. In the defibrillator application, and in any related art application requiring multiple voltages, the related art approach has been to provide individual battery cells connected in parallel and/or series as necessary to supply the voltages and currents required. In cases where high initial currents are required, for example in-rush current associated with starting electrical motors and the like, individual capacitor cells may likewise be wired in parallel with the battery cells to supply the needed starting current. However, battery systems with multiple voltages achieved by connecting a plurality of individual battery cells are expensive to build.
When providing multiple voltages for electronic devices, or wiring capacitors in parallel with battery cells to meet current demands, the battery cells and capacitors of the related art are connected by coupling wires from the individual components (battery cells and capacitors), and then coupling the wires to terminals of an external casing such that all the internal components are within one battery pack. However, there are still multiple battery cells, and possibly capacitors, within the battery pack. As can be appreciated from this description, assembling battery packs in this manner is very labor intensive, thus contributing to the expense of construction.
The capacitor industry has made multiple capacitors in a single winding, as exemplified in U.S. Pat. No. 4,028,595 (hereinafter the '595 patent) to Stockman. In particularly, the '595 patent discloses that multiple sheets of dielectric material with metal film on one side are rolled together on a mandrel to create a first capacitor. After winding a number of turns, a portion of the metal film on each of the sheets of dielectric material is removed, yet the windings are continued with the same dielectric sheets. Additional pieces of dielectric material may be placed between the sheets starting at the location where the portion of the metal on each sheet is removed. In this way, two capacitors, possibly with different voltage ratings, that share dielectric material are produced with a single winding. While it is possible to build capacitors that share dielectric material, the electrolyte of different batteries may not be shared between battery cells.
A second, but related, problem faced by the battery industry is providing batteries of correct amperage capacity. That is, while any battery may have at its output terminals a necessary voltage, the battery may not have the amperage capacity to hold the rated terminal voltage at required amperage demands. The solution of the related art is to couple a plurality of individual batteries in parallel until the total amperage capacity of the battery system matches that of the intended load. This procedure too is labor intensive, and requires battery manufacturers to have significant stocks of batteries of varying capacity to meet possible demand.
Thus, what is needed in the art is a mechanism to provide an integral unit multiple cell battery without the need of externally connecting multiple single cell batteries to produce the desired voltages and currents.